Wing stall after the December update.

[Sarix]

It seems pretty hard now to push the Mi-24 into a deep stall. In my recent flights I can go full aft on the stick without much issue. How accurate is this compared to pre-update stall behaviors where you'd be "stuck" in a nose-up deep stall for a while?

Cheers

[AeriaGloria]

On 12/26/2023 at 6:23 PM, Sarix said:

It seems pretty hard now to push the Mi-24 into a deep stall. In my recent flights I can go full aft on the stick without much issue. How accurate is this compared to pre-update stall behaviors where you'd be "stuck" in a nose-up deep stall for a while?

Cheers

It still happens to me, it's just more smooth the transition.

You hear the blades begin to flap, sometimes some shaking. You will see AOA rapidly increase per G load.

It should be a range of 1.6-1.8 G at low altitudes, and 1.4 G high up. I still find maintaining those numbers to avoid the rotor stall (rotor flapping noise) and to keep speed the most efficiently.

Not sure how you are testing, but a huge part of the phenomenon is rotor stall, so the higher your rotor pitch, the more aggressive it will happen.

Sometimes I still find just decreasing collective 1-3 degrees is plenty to stop it when it happens, which is accurate.

Before the patch you speak of, it would "snap" forward in an oddly quick way when you reduced collective during it.

Now it is much more smooth

[krazyj]

never heard of wing stall on a helicopter, the MR blade can stall if you overspeed or over pitches the blade. 

and its quite normal to go full aft on the helicopter for certain manoeuvres such as precision stops (quick stops) or evasive actions ect. this is usually coordinated with the collective input so an overpitching of the blade doesnt occur. 

the only way to get out of overpitching is to lower coll and move the cyclic forward a little. and once above 40knots normal collective usage can reoccur.  

[Sarix]

2 hours ago, AeriaGloria said:

It still happens to me, it's just more smooth the transition.

You hear the blades begin to flap, sometimes some shaking. You will see AOA rapidly increase per G load.

It should be a range of 1.6-1.8 G at low altitudes, and 1.4 G high up. I still find maintaining those numbers to avoid the rotor stall (rotor flapping noise) and to keep speed the most efficiently.

Not sure how you are testing, but a huge part of the phenomenon is rotor stall, so the higher your rotor pitch, the more aggressive it will happen.

Sometimes I still find just decreasing collective 1-3 degrees is plenty to stop it when it happens, which is accurate.

Before the patch you speak of, it would "snap" forward in an oddly quick way when you reduced collective during it.

Now it is much more smooth

Much appreciate the insight.

I did not "test" per se I just loaded the Mi-24 with some armaments (for weight) and tried to go full stick aft at ~200kph IAS and around 500m, at around 9-11 degs of rotor pitch to see if I could send myself into a deep stall. My impression prior to the patch was that if I go stick aft too quickly it sends the helo into a deep stall which is different from what I was seeing in this patch. Hence the confusion and the post.

It seems that the helo is now much more "lenient" in the stall department.

[admiki]

2 hours ago, krazyj said:

never heard of wing stall on a helicopter, the MR blade can stall if you overspeed or over pitches the blade. 

and its quite normal to go full aft on the helicopter for certain manoeuvres such as precision stops (quick stops) or evasive actions ect. this is usually coordinated with the collective input so an overpitching of the blade doesnt occur. 

the only way to get out of overpitching is to lower coll and move the cyclic forward a little. and once above 40knots normal collective usage can reoccur.  

How many helicopters do you know, that have wing that actually contributes to total lift?

Mi-24 can have wing stall.

How does overspeeding the blades causes stall?

Edited December 28, 2023 by admiki

[krazyj]

27 minutes ago, admiki said:

How many helicopters do you know, that have wing that actually contributes to total lift?

Mi-24 can have wing stall.

How does overspeeding the blades causes stall?

 

I always learn something new, and a blade stall when overspeed was a bit of a stretch but it is infact what happens as the blade goes supersonic the lift drops from the blade and in effect is stalled. 

[AeriaGloria]

7 hours ago, Sarix said:

Much appreciate the insight.

I did not "test" per se I just loaded the Mi-24 with some armaments (for weight) and tried to go full stick aft at ~200kph IAS and around 500m, at around 9-11 degs of rotor pitch to see if I could send myself into a deep stall. My impression prior to the patch was that if I go stick aft too quickly it sends the helo into a deep stall which is different from what I was seeing in this patch. Hence the confusion and the post.

It seems that the helo is now much more "lenient" in the stall department.

200 kmh is only when the phenomenon begins to happen. It only gets severe at 250 kmh, and gets its worst above 300 kmh. Its severity directly correlates with airspeed. Dutch roll is the same

 

6 hours ago, krazyj said:

I always learn something new, and a blade stall when overspeed was a bit of a stretch but it is infact what happens as the blade goes supersonic the lift drops from the blade and in effect is stalled. 

 I believe the blade stall here isnt from overspending blades, the rotor tipsgo about Mach 0.6-0.7 at the tips at full rpm. I believe this rotor stall is from positive AOA. The rotor needs air to come from above it. When the air comes directly from the side, it is more difficult to have smooth airflow but still often okay. But as AOA increases and the air from the airspeed is hitting the rotor from the bottom, then it will really begin to stall as air hits the blades from higher angles. 

 

Edited December 28, 2023 by AeriaGloria